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comparison bn_mp_to_unsigned_bin.c @ 2:86e0b50a9b58 libtommath-orig ltm-0.30-orig

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ltm 0.30 orig import
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:22 +0000
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children d29b64170cf0
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-1:000000000000 2:86e0b50a9b58
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 *
3 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality.
5 *
6 * The library was designed directly after the MPI library by
7 * Michael Fromberger but has been written from scratch with
8 * additional optimizations in place.
9 *
10 * The library is free for all purposes without any express
11 * guarantee it works.
12 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */
15 #include <tommath.h>
16
17 /* store in unsigned [big endian] format */
18 int
19 mp_to_unsigned_bin (mp_int * a, unsigned char *b)
20 {
21 int x, res;
22 mp_int t;
23
24 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
25 return res;
26 }
27
28 x = 0;
29 while (mp_iszero (&t) == 0) {
30 #ifndef MP_8BIT
31 b[x++] = (unsigned char) (t.dp[0] & 255);
32 #else
33 b[x++] = (unsigned char) (t.dp[0] | ((t.dp[1] & 0x01) << 7));
34 #endif
35 if ((res = mp_div_2d (&t, 8, &t, NULL)) != MP_OKAY) {
36 mp_clear (&t);
37 return res;
38 }
39 }
40 bn_reverse (b, x);
41 mp_clear (&t);
42 return MP_OKAY;
43 }